package chapter04.example17;
// 定义类Animal
class Animal {
    public void shout () {
        System.out.println("动物叫......");
    }
}
// Dog类
class Dog extends Animal {
    // 重写shout ()方法
    public void shout(){
        System.out.println("汪汪......");
    }
    public void eat (){
        System.out.println("吃骨头......");
    }
}
//定义测试类
public class Example17 {
    public static void main(String[] args){
        Animal a1 = new Dog();// 通过向上转型实例化Animal对象
        System.out.println("Animal a1 = new Dog():"+(a1 instanceof Animal));
        System.out.println("Animal a1 = new Dog():"+(a1 instanceof Dog));
        Animal a2 = new Animal();//实例化Animal对象
        System.out.println("Animal a2 = new Dog():"+(a2 instanceof Animal));
        System.out.println("Animal a2 = new Dog():"+(a2 instanceof Dog));
    }
}
